Cam grinding apparatus



Oct. 11, 1938. c, GREEN 2,132,949

CAM GRINDING APPARATUS Filed March 10, 1936 2 Sheets-Sheet l 7/ Y2 W F1 1 3mm ULHRENGE J GREEN Oct. 11,1938. c; J. GREEN 2,132,949

I CAM GRINDING APPARATUS Filed March 10, 1936 2 Sheets-Sheet 2 I mun II I llmmafiaa Patented Oc 11, 1938- PATENT tamper, v

OFFICE swam m is, me, Serial m. m

a cum. (on. 51-101) This invention relates to grinding machines, and more particularly to a size controlling apparatus for a cam grinding machine.

One object of this invention is to provide a simple, thoroughly practical size controlling device for controlling the feeding movement of a grinding wheel in a cam grinding machine. Another object of this invention is to provide an electrically controlled sizing apparatus for, a camshaft grinding machine which serves to electrically control the feeding movement of the grinding wheel.

Another object of this invention is to provide a work size controlling apparatus for a cam grinding machine which is automatically moved into an operative position before'the cam has been ground and automatically removed to an inoperative position after the completion of a grinding operation. A further object of this invention is to provide a sizing device for a cam grinding machine which is automatically moved-to and from an operating position in timed relation with the wheel feeding movement.

A further object is to provide such a mechanism in which a fluid pressure actuated means is provided to move the sizing head to and from an operative position. .Other objects will be in part obvious or in part pointed out hereinafter.

This invention accordingly consists in the features of construction, combinations of ele-" ments, and arrangements of parts, as will be exemplified in the structure to be hereinafter described, and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which is shown one of various possible embodiments of the mechanical features of this invention,

Fig. 1 is a fragmentary perspective view together with a wiring diagram of an improved cam grinding machine embodying the size. controlling device;

Fig. 2 is a fragmentary cross sectional view, on an enlarged scale, showing the electrical size control unit in side elevation;

Fig. 3 is a fragmentary plan view of the parts shown in Fig. 2;'and

Fig. 4 is a longitudinal vertical section, on an enlarged scale, taken through the fluid pressure control valve shown in Fig. 1.

A cam grinding machine has been illustrated in the drawings having a base ll carrying a wheel slide H on which a-grinding wheel I3 is rotatably supported. A longitudinally movable table I5 is supported on the front portion of the base I I and is adapted for a longitudi al traversing movement on the machine base II by means of a manually operable hand wheel ll which-is fixed on the outer end ofa shaft II. The inner end of the shaft l1 carries a gear ll meshing with a rack bar It depending from the under side of the work supporting table II. These parts are old and well knownfeatures ofa grinding machine and consequently have not been shown in detail. The grinding wheel II and the wheel slide 12 may be fed toward and from the work supporting table II by a suitable feeding mechanism, such as for example that shown in the prior United States patent to Cole and 'Belden No. 1,911,552 dated May 30, 1938.

In order that work of irregular cross section, such as a cam, may be ground, a mechanism may beutilized whereby the wbrk axis and the grinding wheel axis may be moved relative to the other during the grinding operation to generate a desired contour upon the work blank. In the preferred construction, however, the work supporting mechanism is mounted so that it may rock toward and-from the operative face of the grinding wheel to produce the desired contour upon the camshaft to be ground. As shown in the drawings, a rock bar 25 is provided with trunnions 28 and 21 which extend from opposite ends of the rock bar 28 and are supported in brackets 28 (Fig. 2) on the table it. The bracket for supporting the left-hand end trunnions 26, as shown in Fig. 1, is substantially identical to the bracket 28 shown in Fig. 2. These brackets are held in a fixed position on the table I! by screws 29 and 30. A headstock member 32 and a footstock member 33 may be adjustably supported on the rock bar 25. However, in the form illustrated they are formed integral with the rock bar 25. The head and footstock are provided with work supporting centers 34 and 35 respectively to rotatably support the work piece or camshaft 36 during the grinding operation. The headstock 32 carries a driving member 31 adapted to engage a driving dog 38 which is clamped to one end of the camshaft 36.

A master cam and a follower are arranged to transmit a rocking motion to'the camshaft 36 to cause a movement toward and from the grinding wheel and produce the desired contour. As illustrated, a master camshaft 4| is rotatably mounted on the headstock 32 in axial alignment with the camshaft 36 to be ground. The master camshaft ll comprises a plurality of master cams 42 which are shaped and timed to correspond with the cams to be produced on the finished camshaft. In order that the rotation may rock the bar 25, a bracket member (not shown) is clamped on the table It and is arranged to support a rotatable master cam roller or follower 46. The follower 46 is slidably keyed to the rotatable shaft 41 which is rotatably supported in bearings (not shown). From this construction, it will be readily apparent that rotation of the master cams 42, which are in alignment with the camshaft I6,'against the master to be ground, such as for ehrample that shown in the prior United States patent to Trefethen and Belden No. 1,783,755 dated December 2, 1930.

p A mechanism is provided to yieldably maintain the master cam 42 in contact with the periphery of the master cam roller 46. As shown in the drawings, the rock bar 25 is provided with a projecting arm 60. The lower end of a piston rod 6| is pivotally connected by means of a pin 62 to the outer end of the arm 60 and is slidably supported within a cylinder 61. The cylinder 61 slidably supports a piston 68 which is connected to the upper end of the piston rod 6|. A spring 69 surrounds the piston rod 6| and is interposed between the piston 68 and a cylinder head enclosing the lower end of the cylinder 61. The spring 69 serves to rock the arm 60 and rock bar 25 in a clockwise direction, as shown in Fig. 1, so as to hold t e master cam 42 in operative contact with the master cam roller 46 during the grinding operation and thereby transmits the desired motion to the product camshaft 36 to grind a predetermined contour on the cam being ground. In order to take care of the swinging movement of the arm 60 and piston rod 6|; the cylinder 61 is preferably supported by a circular clamping band I0 which is pivotally connected by a stud II with a fixed bracket 12.

A suitable driving mechanism may be utilized to rotate the master camshaft to be ground. such for example that shown in the U. S. patent to Trefethen and Belden No. 1,783,755 dated December 2, 1930. This feature is not considered to be a part of the present invention and, therefore, has not been illustrated in detail. driving mechanism for rotating the master camshaft, reference may be had to the above-mentioned prior patent.

In order that the master cam 42 may be withdrawn from engagement with the follower roller 46 to permit the follower to be shifted into alignment with the next master cam, a mechanism may be utilized to rock the bar 25 against the tension of the spring 69. In the preferred construction, a device operated by fluid pressure is provided, which includes a cylinder chamber I5 formed in the upper portion of the cylinder 61 carrying the piston 63 slidably mounted therein. When fluid under pressure is admitted into cylinder chamber I5, through a port 11 in a cylinder head I6, the piston 68 is forced downwardly against the tension of the spring 69 to rock the bar 25 and withdraw the master cam 42 and the After the table I5 has been traversed to bring the tion with the next master cam, the fluid pressure For'details of the within the cylinder chamber I5 is cut off and the released tension of the spring 69 moves the rod 6| upwardly to rock the bar 25 and the master cam 42 and the camshaft 36 into operative contact with the master cam roller 46 and the grindingwheel I3 respectively.

As illustrated in the drawings, the wheel slide rotatable feed screw 8| mounted in suitable bearings (not shown) in the base of the machine. A manually operable hand wheel 82 is mounted on arotatable shaft 83. The shaft 83 carries a gear 84 meshing with a gear 85 on the end of the feed screw shaft 8|. By rotating the hand wheel 82, a rotary motion may be transmitted to the feed screw 6I to cause the grinding wheel l3 to approach or recede from the camshaft 36 to be ground, according to the direction in which the hand wheel 82 is rotated.

To operate the fluid pressure mechanism so as to automatically withdraw the cam 42 at the proper time, a valve mechanism operated in timed relation with the moving parts of the grinding machine is provided, and in the preferred construction this valve mechanism is operated in timed relation with the wheel feeding mechanism to rock the bar 25 to an inoperative position when the feed screw 8i is rotated to move the grinding wheel away from the work. As shown in the drawings, the valve mechanism comprises a casing 60 fixed'to the base II. A balanced piston type valve 9| is slidably mounted therein. The extended portion of the piston rod SM is connected to a link 92. In the operation of the mechanism, it is desirable that the valve operate when the feed wheel 82 is turned in either direction, but this mechanism must be so constructed and-arranged that continued movement of the feed mechanism to position the grinding wheel is permissible after the valve has been shifted. To accomplish this, a friction device is provided, as illustrated in Figs. 1 and 4. As illustrated, the link 92 is connected by a pin 63 to a downwardly extending arm 94 of a friction device 95. The friction device comprises two semi-circular shaped members which are adapted to mate with the forwardly extending projection 96 of the feed screw M. The two halves of the clamping ring are connected by means of bolts 91 and 96 which pass through clearance holes in the projecting lugs 99 and I00 in the upper friction member I0! and through the lugs W2 and I03 in the lower portion of the friction device 95. A pair of springs I04 and I05 surround the projecting ends of the bolts 91 and 96 and serve to yieldingly clamp the members 95 and I0! to the shaft 96. Nuts I06 and I01 are provided on the lower ends of the bolts 91 and 98 and serve to adjust the tension of the springs I04 and I05 so that the members 95 and IM may be caused to' frictionally engage the shaft 96 with the desired tension.

It will thus be seen from this construction that the turning of the hand feed wheel 82 is transmitted through the friction device 95, the arm 94, the link 92, to slide the valve stem 9I within the valve casing so as to control the rocking movement of the bar 25. The motion of the valve stem 9i continues until the valve pistons reach the other end of the valve casing 90, after which the feed screw 8i and the shaft 96 extending therefrom are rotated against the friction of the device 95.

The valve 90 is of the piston type having valve with the valve stem Fluid under pressure from a source (not shown), such as a pump and reservoir within the base, passes through a pipe II4 into a valve chamber I I6. In the position of the valve parts, as illustrated in Figs. 1 and 4, fluid is exhaustedfrom the cylinder chamber 16 through the port ",a. pipe I I6, into a passage I I1 within the valve casing which opens into a valve chamber II6 between-the valve pistons III and III and out through a pipe I I 9 into the reservoir. Fluid under pressure from a gauge operating mechanism to be hereinafter described exhausts through a. pipe I20 into-a passage I 2I inthe valve casing which enters intoa valve chamber I22 between the pistons I II and II2 and passes outwardly through an exhaust pipe I23 into 'the reservoir. A throttling valve is provided to control the exhaust of fluid through the'pipes H6 1 and I20. As illustrated,a throttle valve member I24 is provided to control the passage of exhaust fluid through the passage I I1 so as to control the rocking movement of the rock bar 26. A valve member I25 serves to throttle the passage of fluid through the passage I2I so as to control the movement of the sizing device to be hereinafter described. The valve stem 0| and the pistons IIO, III, H2 and II3,-as shown in Figs. 1 and 4, are in an operating position with the master cam 42 in contact with the master cam roller 46, and the product cam on the shaft 36 is in operative engagement with the grinding wheel I .3. When the product cam has been ground to a predetermined size and contour, the feed screw 6| is rotated to remove the grinding wheel from operative contact with the work. During the initial turning of the feed screw 6I, the extended portion '96 is rotated to rock the friction device 95, the link 92 and to move the valve stem 9| toward the left, as viewed in Figs. 1 and 4. This movement shifts the valvepiston II2 toward the left, which serves to open the passage I 2I to the chamber II5 so as to admit fluid under pressure to operate the sizing device to be hereinafter described and'continued movement of the valve serves to open the passage I I1 to the valve chamber II5 so as to admit fluid under pressure through the pipe I I 6, port 11, into cylinder chamber 15 to rock the bar 25 me counterclockwise direction, as shown in Fig. 1, to remove the master cam 42 and the product camshaft 36 to an inoperative position out of contact with the master cam roller 46 and the grinding wheel I3 respectively.

In order that the feed screw may be turned automatically to move the wheel slide I2 in either direction toward or from the camshaft 36, a power driven mechanism is provided which includes a pulley I30 driven by a belt I3I from a suitable source of power. The pulley I30 is fixedly mounted on a rotatable shaft I 32 which is supported in bearings (not shown) in the base II of the machine. The shaft I32 is provided with a worm I33 meshing with a gear I34 journaled on a transverse shaft I35. Power may be transmitted from the gear I34 to rotate the feed screw 8| by a direct driving connection but in the preferred construction a tumbler gear I36 is mounted upon a swinging arm I31 which is pivotally supported to swing about the shaft I35 as a. pivot. The gear I36 in turn meshes with a gear I38 journaled on the shaft I35 and secured to the gear I34 so that as power is applied to the pulley I30, the gear I38 transmits power to the tumbler gear I36 in all positions of the arms I31.

A lever I43 is fixed on the outer end of the shaft I36 to turn the arm I31 and hence to permit manual control of the tumbler gear I36. By movement of the lever I40 toward the left, as viewed in Fig. 1, said-tumbler gear I36 is thrown into mesh with the gear 36 on the outer end of the feed screw II, thereby causing arotation of the feed screw in the direction to feed the grinding wheel I3 toward the camshaft 36. .A spring pressed plunger I is mounted on the front of the machine base and contacts with a projection on*th'e rear of the lever I 46 and serves to hold the lever in its operative position with the tumbler gear I36 in mesh with the gear 66 to cause an infeedingmovement of the grinding wheel I3.

To obtain areverse feed, thatis to move the grinding wheel rearwardly, after the grinding operation has been completed, a mechanism is provided for rotating the feed screw by power in the opposite direction to move the grinding wheel I3 rearwardly, preferably at a higher rate of speed than that at which it moves forwardly in its grinding feed movement. To accomplish this, a gear I46 is mounted on the shaft I35 to be driven by power imparted to the gear I34, and said gear I46 meshes with a gear I46 on a shaft I41. The shaft I41 also carries a gear I46 which is formed either integralwith or flxed to the gear I46. A gear I50 is mounted on the feed screw and meshes with a tumbler gear I 5| which is rotatably supported on a stud I52 carried by a bell crank lever I53. The bell crank lever I53 is pivoted to swing upon a portion of the feed screw shaft 36 so that it may be'moved to roll the gear I5I into mesh with the gear I46 on the shaft I41. It will be noted that the gears I46 and I40 constitute intermediate gears to give a reversal in direction of rotation to the feed screw 8|. It will be readily seen from the construc tion described that by throwing the gear I36 into mesh with the gear 65, a slow forward infeeding movement of the grinding wheel I3 toward the camshaft 36 is obtained and that by rolling the tumbler gear I5I into mesh with the intermediate gear I43, a rapid reverse or rearward feed is produced to move the grinding wheel I3 rapidly away from the camshaft 36 to an inoperative position.

Automatic means for controlling the feeding mechanism in grinding successive cam blanks on an integral camshaft to a predetermined contour and size will now be described. This includes a calipering device arranged to contact with the cam being ground during the grinding operation and also a mechanism responsive to the action of the calipering device after the grinding operation has progressed and the cam being ground has been reduced to a predetermined contour and size. The calipering device may be combined with a steadyrest or mounted on a flxed part of the machine or work table but, as illustrated, it has been shown as mounted on a bracket I60 which is fixed to the base II by screws iii and I62. A calipering head I63 is pivotally supported on the bracket I60 by means of the pivot pin or trunnion I64. The sizing head I63 comprises a pair of upwardly extending arms I66 and I 66 whichslidably support a plunger I 61. The plunger I61 carries at its outer end a roller I 66 supported by a stud I69. The roller I66 is preferably supported in a slotted end portion in the plunger I61 and is arranged to engage the periphery of a cambeing ground on the camshaft 36 during the grinding operation.

The contact roller I68 is maintained in operative contact with the cam being ground by means of a spring I10 which surrounds the plunger I61 and is interposed between the arm I68 and: an adjustable collar "I which is adjustably sup-- ported on a threaded portion I12 on the plunger I61. By adjusting the collar !1I relative to the plunger I61, the tension of the spring I10 may be adjusted to maintain the contact roller I68 in engagement with the cam being ground at the desired pressure. v

The calipering device preferably operates .a

pair or contact members, one acting toterminate V indexing the table I 5 and camshaft 35 and master the power infeed of the grinding wheel and ,permit the finish grinding operation to take place while the grinding wheel slide remains I15 carries-a. pivot pin I16 which supports'a pair of pivotally mounted contact members I11 and I18. The contact members; I11. and I18 have. a

downwardly projecting arm I19 -which -is1 ar-.

ranged in the path .of the adjustable collar I-1I. A spring I is interposed between: thedownwardly extending arms 119: on each of the con 1 wheel feeding movement; mechanism may ccmprisewfluid pressure cylinder 2 which is r tact members I11 and I18 and the arm'- I65 normally tends to-roclgithecontact arms.;I11 and I18 in a counterclockwisedirection, (Fig. 2). The contact member I11 is connected by a wire I with a binding post I86 and the contact 'member 118 is connected by a wire I8 1 'with 'a binding post I88. The binding posts I86'and I88 serve to connect the sizing head witn the wheel.

feed operating mechanism. I V r The arm" I66 is provided with; an insulatingblock I90 atits upper end which is provided with 4 a pair ofadjustablecontact screws I9I and I92 which cooperates with ,the' pivotally mounted contact members l11'and' I18 respectively. Each of the contact screws I8I and I92- are' connected Y by a single contactmember I93 with a binding.

post I94; ."-The upper portion of, the pivoted' contact arm I11is preferably iermedJas-aflat spring contact member I-I1into engagement wit'i'i the' adjustable contact' screw I9I, serving. to -make" theflfirst contact :which is connected in amtinner to be hereinafterdescribedfto stop the infeed ing' movement, of the grinding wheel butallowing the wheelitojremain-in eperative contact "with" the'c'am being grc-und to finishgri'nd the same. The grinding operation onthe'cam blank continues, 'and '-thef adjustable collar I1I moves toward the left, asviewed in Fig; 2,'as.per-

rnitted'by-a reduction in size of the cam, sex n the spring I18 which carries the contact member I11 until'theadjustable collar IEI engagesthe arm I 19 at the lower end of-the contact arm I18 and swings the 'contact- I18, into engagement with the contact at 'the end'of the adjustable 1 screw I92 which serv'es in a manner to be here inafter described to lcau'se-a rapid rearward movement of the grinding wheel.

. The sizing head is preferably operated enlalow voltage or low energy. current in a manner similar to that shown in.the prior patent to Cole and Belden No. 1,911,552. j In the preferred construction, a battery 200 serves to supply'current which is connected to be controlled by the calipering head I63. One terminal 01 the battery 208 is connected by means oi'a knife switch 2! and a wire 202 with the binding post I94 which is connected to both of the adjustable screw contact members I9I and I92. The other terminal of the battery 200 is connected "to a relay 263 anda relay 204. An electrcrnagnet 205 ofthe relay 203 is connected'in' series by a wire 206' with the binding'post' I86, and-an electromag'net 201 .of the relay 205' in connected in series by'a wire 208 with the binding post'l88 on the sidehead I53.

To facilitate loading of the machine as well as .cam 42 longitudinallypto-grind successive cams on-the camshaft-'36, it is desirable to provide, a means ior'swinging the sizing head to an inoperati've' position. during the. indexing and loading -peri0ds.-. The sizing head I63 ispivotally mounted on a stud I64 which is supported in the Mack-- et I60. fixed to the base'foi the machine. 'An adjustable; stop screw 210 serves to locate thesizln 'head. in;. anoperatingfpositionso that the of the pin 1 69, the,axis of the workpiece. 36 and the axis-bf the-grinding wheel lie in the same horizontal-plane.- In order quickly to remove the sizing: head I63 -to an inoperative position, afluid pressurefmechanism' is provided whichis' preferablyQ'operated in-tin'iedv relationship with the fixed to thefjbracketfl6ll l The cylinder. m con-- tains-a'fpiston 2I2 which is mounte-i onthe lower [end of "aLpiston rod 21:3,- g The upper end of the. .-pis ton' rod'isfcoiinectedhyastud 214 with an.

arm 2I5 projecting from the 's'izingfhead I63.

Ifhe gauging headisyieldingly heldlin' an oper'atv 1111; positionby' means of a spring 2| 6 which surroundsflthe 'pistonrod 213 and is interposed'be tween a collar-2E1, and the upper surface of a.

cylinder-headiilfl. The spring 2I6 serves'to rock the gauging head in a vcountercl'q'ekwise direction intothe position illustrated. in.1 '"i'g.- 2.?

wheel"I3,-the1"valve piston 9Ifis' moved, toward,

*Whe'j thefeedscrew 'e lfis "turnedto cause .a rearward feedingQnmovementof the grinding the leit, as viewed in Figs-. land .4, as above de- I v seribed-,; servin"g5. to admit fiuid' under pressure I through a" pipe-I20 into'a, cylinder chamber 2I9" i dew-Wa m e n -p t e i n 212; ine" asindieated injFig.

a sufficient;distance from the cams on. 'the camot; ,a'n'd continued- 'movement H V v rock'itheq silzinghead I63:in aclockwfie dire 1on1 into a dotted lineipos'itiom-i'1 H ,iso'th'atthe contact-roller- I I 68 is,movedinto ganjinoperative position. I68a 1 60 shaft so'that-the-Shaft maybe readily-indexed ownward movement ;or the""pi ston--' a-t s ithem r s4: y smn" "sain lelo'ngate slot 2 20 i;1i";the bracket "I60 until p 64; engages-L the lowersurface ofl finish. ground camshaft-maybe readily removed f,

In the operation-of :thls sizing; apparatus on" a andithe lever [401s movedtoward-the left into tumbler gear- I36into. mesh with the .gea'r'85 ;mounted on the shaft96 which extends fromthe' the position as viewed in 1, to throw the feed screw 8I so' as to start an infeeding move- .;ment ofthe grinding wheel slide I2 and the grindareas ing wheel is. This movement serves through the gear 84 and shaft 88 to rotate the hand wheel 82 which in-turn rotates a friction disk 221 to close a knife switch 2", as is more fully described in the above-mentioned U. S. patent to Cole and Belden No. 1,911,552. when the infeeding movement starts, the friction device 88 moves the link 92 and valve stem 8| toward the left (Figs. 1 and 4), untilthe valve pistons IIII, III, (I2 and I I3 assume the positions illustrated i -Figs. -1 and 4. This movement allows fluid within the cylinder chamber 15 to exhaust and.allows the released tension of the spring 88 to rock the bar 25 into operative position'with the master cam, 42 in contact with the follower roller 48 and the cam to be ground in operative position with rela tion to the grinding wheel I3. At the same time, fluid under pressure is allowed to exhaust from the cylinder chamber 2I8,.releasing the tension of the spring 2I8, which rocksthe sizing head I63 in a counterclockwise direction (Fig.2) into the full line position, as indicated in Fig. 2,- so that the feeler roller I88 is in operative contact with the cam being ground. The infeeding movement of the grinding wheel I8 continues until the adjustable collar IlI engages the arm I18 to rock the contact member I" into engagement with the adjustable contact member IQI. The closing of contacts I11 and I9I serves to close a circuit and through the wire 206 to energize the magnet 205 on relay 203, so as to close a circuit between the high voltage lines 22I and 222 to, energize a solenoid 225 which serves to move the lever I40 toward the right, as viewed in Fig. 1 to throw the tumbler gear I36 outof mesh'with the gear 85 on the feed screw shaft 96, thereby stopping the infeed of the grinding wheel I3, but allowing the wheels to remain'in grinding contact with the work to allow the wheel to spark-out or finish grind the cam being ground. The grinding continues andthe roller I68 advances toward the work axis as the cam is reduced in size. The adjustable collar I'll continues to rock the arm I19, flexing the contact spring I'll until the collar IlI engages and rocks the contact member I18 through a sufficientextent so that it engages the adjustable contact screw I92. Closing of the circuit by contacting of the member I18 and the contact screw I92 serves to energize the electromagnet 201 of the relay 204 which in turn makes a circuit between the higher voltage or higher energy circuit indicated by the wires 22I and 222 to energize a solenoid 226 which serves to rock-a lever 223 in a counterclockwise direction against the tension of a spring 226, thereby rocking the bell crank I53 in a counterclockwise direction to rock the reverse tumbler gear I5I into engagement with the gear I48 to cause a rapid reverse movement of the feed screw 8I to rapidly move the wheel slide I2 and grinding wheel I3 to an inoperative position. Duringthe rearward movement of the slide, the shaft 83 is rotated ina reverse direction by means of the gear 84, causing the friction plate 221 to rotate until the abutment 22l engages and opens the knife switch 20I to break the low voltage current from the battery 20'! and thereby render the sizing head inoperative until the knife switch 20'I is again closed at the start of the next grinding operation.

During the initial reverse movement of the feed screw 8| and its projecting shaft 96, the link 92 and valve piston 9| are moved toward the right, as viewed in Figs. 1 and 4, so as to admit fluid underpressurefromthe-pipe line Il4flrstthrough the pipe I24 into the cylinder chamber 2I8 to rock the sizing head I to an inoperative position, as indicated in broken lines in Fig. 2, and then to admit fluid under pressure through the pipe III into the cylinder chamber It to cause the rock bar 25 to rock ina counterclockwise direction (Fig. 1), to separate the master .cam 42 from the master cam roller 48 and to remove the cam being ground on the camshaft 86 from operative engagement with the grinding wheel I8. The table II may then be indexedlongitudinally tobring the next cam blank into operative engagement with the grinding wheel, and the cycle of grinding is then completed. This cycle of operation is continued until all of the cams onthe shaft have been ground to a predetermined size and contour, after wnich the camshaft' 86 may be removed and a new camshaft mounted in place for a grinding operation.

' It will thus be seen that there has been provided by this invention apparatus in which the various objects hereinabove set forth together with many thoroughly practical advantages are successfully achieved. As various possible embodiments might be made of the mechanical features of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinbefore set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

I claim:

1. A sizing device for a cam grinding machine comprising a sizing head having a movable contact member arranged to continuoosly engage the periphery of a cam during the grinding operation, an adjustable member moved by said contact member, a pair of adjustable electrical contacts carried by said head and actuated by \said contact member after the cam has been ground to a predetermined extent to stop the infeed of the grinding wheel, and means including a second pair of electrical contacts carried by said head and arranged to reverse the wheel feeding movement when the cam has been finish ground to a predetermined size and contour.

2. A sizing apparatus for a cam grinding machine comprising .a movable sizing head, a movable contact member mounted on said head and ieidinsly m ntained in contact with the periphery of said cam during grinding, means including a pair of electrical contacts on said head which are actuated by said movable contact member when the cam has been ground to a predetermined extent tostop the infeed of the grinding wheel, and means including a second pair of electrical contacts on said head which are actuated by movement of said contact member to cause a rearward movement of the grinding wheel when the cam has been ground to a predetermined size and contour.

3. A cam grinding apparatus comprising-a rotatable grinding wheel, a rotatable work support, a reversible feeding mechanism for feeding the grinding wheel and work support relatively toward and from each other to grind a cam blank to a predetermined size, means including a master cam and followerto move the grinding wheel and work support transversely and relatively toward and from each other during the grinding operation to grind the cam blank to a predetermined contour, a sizing device including a movable feeler which continuously engages the ing to automatically control saidfeeding mech-- anism, a pair. of adiustable electrical contacts actuated by said feeler to stop the transverse feeding movement betweenthe wheel and work after the cam has been ground to a'predetercontour. i

mined extent, and means including a second pair 01' electrical-contacts'actuated by said teeler to reverse the feeding mechanism when the can has been ground. to a predetermined size and 4.."A'camgrindlng apparatus comprising a rotatable grinding wheel, a 'work support, a reversiblefeeding mechanism ior feeding the grinding wheel toward and from the work, meansim cluding a master cam and roller to move the work support toward" and from'the grinding wheel to grind a cam blank to a predetermined contour, a sizing device including, a movable feeler which continuously engages the periphery of the ca'nr being ground during grinding to automatically-control said feeding mechanism so: as

to grind'successive cam blanks to -a prede termined size, and automatic means" operated in timed relation with the rearward movement of- -the grindingwheel to move the sizing, device to an inoperative position sofas to permit a traversing movement of the work support to present grinding wheel.

' 5. A cam grinding" apparatus comprising a rovtajtable grinding wheel, a work support, a feeding mechanism for feeding the grinding wheel toward and from the work, means including a *master cam'and roller to move the work support toward and from the grinding wheelto grind a cam blank to a predetermined contour, a sizing devicelinciuding a" movable feeler which continuously engages the' periphery of. the cam being ground during grinding to automatically control .saidifeeding-mechanism, and automatic means operated in timed relation with the forward feed ing movement-of-the grinding wheel to movethe 'sizingdevice int'oanoperative positionwith the .7

feelerkfifn contact with ithecam and operated in timed relationjwith the rearward movement of the grinding wheel after agrinding operation to -move thesizing'device to an inoperative position- 'so' as to' permitl'atraversing" movement .of' the I work support to'.present the next cam i'nto'oper ative relation with the grinding wheel: a

'6. A camgrindingiapparatus-comprisinga ro- Itatable:grindingwheel, a work support, 'a feed I -,in g; mechanism for; feedingjthe grinding wheel;-

-7 7' gsatowardandi rrom-the work, .means including 'a' master cam and roller to move the work support toward and from the grinding'wheel to grind a cam blank to a predetermined contour, a sizing relation with the wheel feeding movement to move said master cam into operative relation with the master cam roller and to move the sizing J device so that the contact member engages the periphery of the 'cam being ground.

"7. A cam grinding apparatus comprisinga ro-j tatable grinding wheel, a worksupport, a feedingmechanism for feeding the grinding 1 wheel toward and from -the work, means including a master cam and roller to move the work support toward and from the grinding wheel'to grind a cam blank to a predetermined contour, a' sizing 1 20 Y device including a movable feeler which-con tinuously engages the periphery of the cam being ground during grinding to automatically control the cam size, andautoniatic means operated in "timed relation with the rearward movement of the grinding wheel to se a ate the master cam -from the roller and to move the sizing device to an inoperative position so as to facilitate a; trav- --ersing movement of the work support to present the next-roam .into operative relation with the' the next master cam into'operative relation with the grinding wheel. I p. V I

8. A cam grinding machine comprising a to:

tatable grinding wheel; a work Isupport ,mov able toward and from the grinding wheel, means for feeding the grinding wheel toward andfirom the work support; means for supporting acamshaft on said support in operative relation with the grinding wheel, means-including aset of master cams and a cam follower arranged'to move thesupport toward-and from" the grinding wheel to 5 cause the latterto grind-a predeterminedv contour on the cam blanks, nieans for traversing the work support and the grinding 'WheeI 'Iongitudidevice having a movable Zfeeler or contact memher which continuously engages r the periphery of acanr duringthe grinding operation to control said feeding mechanism, means operated by nally relative to each other, .a movable sizing therearward movement of the wheel to move the. master cam away from the follower, and means Y associated therewith to .move the sizing device tovan inoperative position to permiteither aftrav er'sing movementof the camshaiftor-aremoval -ofithej same after the last has been ground; I r i I 

